1. Field of the Invention
This invention relates to PWC, specifically to a kit for non-permanently converting a stand up PWC into a sit down.
2. Background--Prior Art
Currently, Personal Watercraft (PWC) consist of three primary classifications. There are single person "stand ups", 2 and 3 rider "sit downs", and sit in "jet boats" with seating for 3 or more passengers. Although all are classified as PWC, each has its own distinct advantages and disadvantages. Single person stand up skis are the smallest PWC, have the least utility and are widely regarded as the most difficult to ride. The hull is designed with minimum roll and longitudinal stability which enables extreme maneuverability. At low speeds, even average size riders must hang over the stern to remain upright. At planing speeds, riders must quickly shift their body weight, and therefore the overall Center of Gravity (CG), to maintain directional control and keep the nose from submerging. All stand up PWC have an open footwell and pivoting handle pole to allow maximum freedom for the above maneuvers.
Jet boats do not require the driver to shift his weight for control, have the largest payload capacity, and offer a statically stable platform for activities such as fishing or sunbathing. Multi-person sit down skis are positioned between stand ups and jet boats with regard to stability vs. control or utility vs. maneuverability capabilities. Their size and configuration limit the operator's ability to affect the overall CG for control purposes. Therefore, sit down skis have greater stability design requirements then stand up skis. For example, the bow of a sit down ski is enlarged to prevent submerging due to elevated pitch loads created by seated riders. Also, they have increased roll and longitudinal stability to permit low speed handling from a seated position and reduce deep water boarding difficulty.
Sit down skis have become the most popular selling class by having a popular ratio of thrill and utility. This ratio has been achieved mainly by engine performance enhancements. Until now, consumers that want the ultimate maneuverability of a stand up and the utility of a sit down must buy one of each. This option is not popular since owning two PWC doubles maintenance, storage, trailer capacity and operating cost. Additionally, one of the skis must be left behind when going on trips.
A search of the prior art did not disclose any patents that address the requirements for non permanently converting a stand up into a sit down type PWC. However, the following patents are related and indicative of the state of the art. U.S. Pat. Nos. 5,746,150, 5,443,028, and 5,353,730 each provide a structure, sized and arranged similar to a small boat, that uses a PWC for propulsion. These designs provide a docking bay or bays at their rear that allows a PWC to be inserted and temporarily secured. The combination forms a jet boat class vessel with a passenger area and overall CG located forward of the docked PWC. The main requirement of the attachment interface is to securely couple the two units in a fashion that allows easy removal and integration with many different PWC brands and models. The size and arrangement of these designs alleviates the necessity to address the unique stability, performance and ergonomic requirements for converting a stand up ski into a sit down.
U.S. Pat. No. 5,685,254 provides a permanently attached second hull that makes stand up PWC easier to ride for full sized adults. A seat is not provided nor is any means to fix the handle pole. The second hull provides a limited increase in stability by enlarging the PWC bottom and 4 sides. The configuration requires a secondary ride plate and jet nozzle extension due to interference with the water jet operation. Also, the structure requires modification of the PWC and tools for installation.
U.S. Pat. No. 4,694,770 provides a multi-piece hull that simplifies the low speed handling of stand up PWC. Application of the structure leaves the footwell and handle pole unrestricted so that stand up operation is uninhibited. The structure improves roll stability by extending the lateral hull surface in contact with the water. The structure does not extend the hydrodynamic bow of the PWC and cannot extend rearward past the PWC transom without restricting the water jet turning effectiveness. Therefore, longitudinal stability is limited by the length of the PWC and insufficient for multiple sit down riders. Additionally, the location of the hull separations increases drag sensitivity due to fit variation and renders the vehicle inoperable should an attachment fail or become lost overwater. Finally, the chair configured across the stern prohibits operating with multiple riders and is restrictive for deep water boarding.
As discussed above, stand up PWC do not have the buoyancy, stability or structure to support multiple seated riders and no prior art addresses these requirements with a non permanently applied kit. In addition to increasing buoyancy and stability, such a design must satisfy unique ergonomic, installation, manufacturing and packaging requirements. Extensive research, development and testing has been completed with a prototype kit to ensure the following invention satisfies all of these requirements while maximizing performance with an inherently fail safe design.